Synchronisation and broadcasting between base station and user equipment

ABSTRACT

A base station for a mobile telecommunications system has circuitry configured to communicate with at least one user equipment, wherein the circuitry is further configured to set a first subcarrier spacing for transmission of at least one synchronization signal; and set a second subcarrier spacing for transmission on a physical broadcast channel, wherein the first subcarrier spacing differs from the second subcarrier spacing.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.16/469,185, filed Jun. 13, 2019, which is based on PCT filingPCT/EP2017/083955, filed Dec. 20, 2017, which claims priority to EP16206517.1, filed Dec. 22, 2016, the entire contents of each areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure generally pertains to a base station and userequipment for a mobile telecommunications system, which generallypertain to transmission and reception of synchronization signals.

TECHNICAL BACKGROUND

Several generations of mobile telecommunications systems are known, e.g.the third generation (“3G”), which is based on the International MobileTelecommunications-2000 (IMT-2000) specifications, the fourth generation(“4G”), which provides capabilities as defined in the InternationalMobile Telecommunications-Advanced Standard (IMT-Advanced Standard), andthe current fifth generation (“5G”), which is under development andwhich might be put into practice in the year 2020.

A candidate for providing the requirements of 5G is the so-called LongTerm Evolution (“LTE”), which is a wireless communications technologyallowing high-speed data communications for mobile phones and dataterminals and which is already used for 4G mobile telecommunicationssystems. Other candidates for meeting the 5G requirements are termed NewRadio (NR) Access Technology Systems (NR). An NR can be based on LTEtechnology, just as LTE was based on previous generations of mobilecommunications technology.

LTE is based on the GSM/EDGE (“Global System for MobileCommunications”/“Enhanced Data rates for GSM Evolution” also calledEGPRS) of the second generation (“2G”) and UMTS/HSPA (“Universal MobileTelecommunications System”/“High Speed Packet Access”) of the thirdgeneration (“3G”) network technologies.

LTE is standardized under the control of 3GPP (“3rd GenerationPartnership Project”) and there exists a successor LTE-A (LTE Advanced)allowing higher data rates than the basic LTE and which is alsostandardized under the control of 3GPP.

For the future, 3GPP plans to further develop LTE-A such that it will beable to fulfill the technical requirements of 5G.

As the 5G system will be based on LTE or LTE-A, respectively, it isassumed that specific requirements of the 5G technologies will,basically, be dealt with by features and methods which are alreadydefined in the LTE and LTE-A standard documentation.

In LTE, a Physical Broadcast Channel is known which is used forbroadcasting system information, such as the master information block(MIB). The PBCH broadcasts a limited number of parameters, which areessential for an initial access to a cell. These parameters pertain, forexample, to the downlink system bandwidth, the Physical Hybrid ARQIndicator Channel structure, and the most significant eight-bits of theSystem Frame Number.

Typically, in LTE, the UE which wants to get access to a cell performs acell synchronization and acquires a physical cell ID, time slot andframe synchronization, on the basis of which the UE will be able to readthe system information blocks. When the UE tunes to a specific channelit typically finds the primary synchronization signal (PSS). In LTE, thePSS is located in the last OFDM (Orthogonal Frequency-DivisionMultiplexing) symbol of the first time slot of the first subframe(subframe 0) of a radio frame. In a next step, typically, the UE findsthe secondary synchronization signal (SSS), wherein the symbols of theSSS are located in the same subframe as the symbols of the PSS. Based onthe SSS, the UE is able to obtain a physical layer cell identity groupnumber (e.g. in a range from 0 to 167). On the basis of thisinformation, the UE is able to get the location of reference signals ofthe cell, wherein reference signals may be used for channel estimation,cell selection and reselection, handover procedures and the like.

Although there exist techniques for providing the primary and secondarysynchronization signals and transmission over a physical broadcastchannel, it is generally desirable to improve the existing techniques.

SUMMARY

According to a first aspect, the disclosure provides a base station fora mobile telecommunications system comprising circuitry configured tocommunicate with at least one user equipment, wherein the circuitry isfurther configured to set a first subcarrier spacing for transmission ofat least one synchronization signal; and set a second subcarrier spacingfor transmission on a physical broadcast channel, wherein the firstsubcarrier spacing differs from the second subcarrier spacing.

According to a second aspect, the disclosure provides a user equipmentfor a mobile telecommunications system comprising circuitry configuredto communicate with at least one base station, wherein the circuitry isfurther configured to receive at least one synchronization signal andreceive a transmission over a physical broadcast channel, wherein thesynchronization signal is transmitted with a first subcarrier spacingand the transmission over the physical broadcast channel is transmittedwith a second subcarrier spacing, wherein the first subcarrier spacingdiffers from the second subcarrier spacing.

According to a third aspect, the disclosure provides a base station fora mobile telecommunications system comprising circuitry configured tocommunicate with at least one user equipment, wherein the circuitry isfurther configured to indicate, based on a primary synchronizationsignal, a specific subcarrier spacing for a physical broadcast channel.

According to a fourth aspect, the disclosure provides a user equipmentfor a mobile telecommunications system comprising circuitry configuredto communicate with at least one base station, wherein the circuitry isfurther configured to receive at least one primary synchronizationsignal; and to determine, based on the received at least one primarysynchronization signal, a subcarrier spacing of a physical broadcastchannel.

According to a fifth aspect, the disclosure provides a base station fora mobile telecommunications system comprising circuitry configured tocommunicate with at least one user equipment, wherein the circuitry isfurther configured to transmit symbols on a physical broadcast channel,wherein symbols are transmitted with a subcarrier spacing and modulationsymbols are repeated in consecutive resource elements in the frequencydomain.

According to a sixth aspect, the disclosure provides a user equipmentfor a mobile telecommunications system comprising circuitry configuredto communicate with at least one base station, wherein the circuitry isfurther configured to receive symbols on a physical broadcast channel,wherein symbols are transmitted with a subcarrier spacing and modulationsymbols are repeated in consecutive resource elements in the frequencydomain.

According to a seventh aspect, the disclosure provides a base stationfor a mobile telecommunications system comprising circuitry configuredto communicate with at least one user equipment, wherein the circuitryis further configured to transmit symbols in a physical broadcastchannel by applying a phase ramp.

According to an eighth aspect, the disclosure provides a user equipmentfor a mobile telecommunications system comprising circuitry configuredto communicate with at least one base station, wherein the circuitry isfurther configured to receive symbols over a physical broadcast channel,wherein a phase ramp is applied to at least one symbol.

Further aspects are set forth in the dependent claims, the followingdescription and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are explained by way of example with respect to theaccompanying drawings, in which:

FIG. 1 illustrates an embodiment of a radio access network with a LTEeNodeB and a NR eNodeB;

FIG. 2 illustrates a LTE FDD frame and a resource block;

FIG. 3 illustrates a flowchart for a mobile telecommunications systemmethod;

FIG. 4 illustrates a flowchart for a further mobile telecommunicationssystem method;

FIG. 5 illustrates a subcarrier scaling;

FIG. 6 illustrates a flowchart for a further mobile telecommunicationssystem method;

FIG. 7 illustrates the functionality of a receiver algorithm; and

FIG. 8 illustrates inclusion of a multi-purpose computer which can beused for implementing a base station and/or user equipment.

DETAILED DESCRIPTION OF EMBODIMENTS

Before a detailed description of the embodiments under reference of FIG.1 is given, general explanations are made.

As mentioned in the outset, in general, several generations of mobiletelecommunications systems are known, e.g. the third generation (“3G”),which is based on the International Mobile Telecommunications-2000(IMT-2000) specifications, the fourth generation (“4G”), which providescapabilities as defined in the International MobileTelecommunications-Advanced Standard (IMT-Advanced Standard), and thecurrent fifth generation (“5G”), which is under development and whichmight be put into practice in the year 2020.

A candidate for providing the requirements of 5G is the so-called LongTerm Evolution (“LTE”), which is a wireless communications technologyallowing high-speed data communications for mobile phones and dataterminals and which is already used for 4G mobile telecommunicationssystems. Other candidates for meeting the 5G requirements are termed NewRadio (NR) Access Technology Systems (NR). An NR can be based on LTEtechnology, just as LTE was based on previous generations of mobilecommunications technology.

LTE is based on the GSM/EDGE (“Global System for MobileCommunications”/“Enhanced Data rates for GSM Evolution” also calledEGPRS) of the second generation (“2G”) and UMTS/HSPA (“Universal MobileTelecommunications System”/“High Speed Packet Access”) of the thirdgeneration (“3G”) network technologies.

LTE is standardized under the control of 3GPP (“3rd GenerationPartnership Project”) and there exists a successor LTE-A (LTE Advanced)allowing higher data rates than the basic LTE and which is alsostandardized under the control of 3GPP.

For the future, 3GPP plans to further develop LTE-A such that it will beable to fulfill the technical requirements of 5G.

As the 5G system will be based on LTE or LTE-A, respectively, it isassumed that specific requirements of the 5G technologies will,basically, be dealt with by features and methods which are alreadydefined in the LTE and LTE-A standard documentation.

In LTE, as mentioned above, a Physical Broadcast Channel is known whichis used for broadcasting system information, such as the masterinformation block (MIB). The PBCH broadcasts a limited number ofparameters, which are essential for an initial access to a cell. Theseparameters pertain, for example, to the downlink system bandwidth, thePhysical Hybrid ARQ Indicator Channel structure, and the mostsignificant eight-bits of the System Frame Number.

Typically, as mentioned above, in LTE, the UE which wants to get accessto a cell performs a cell synchronization and acquires a physical cellID, time slot and frame synchronization, on the basis of which the UEwill be able to read the system information blocks. When the UE tunes toa specific channel it typically finds the primary synchronization signal(PSS). In LTE, the PSS is located in the last OFDM symbol of the firsttime slot of the first subframe (subframe 0) of a radio frame. In a nextstep, typically, the UE finds the secondary synchronization signal(SSS), wherein the symbols of the SSS are located in the same subframeas the symbols of the PSS. Based on the SSS, the UE is able to obtain aphysical layer cell identity group number (e.g. in a range from 0 to167). On the basis of this information, the UE is able to get thelocation of reference signals of the cell, wherein reference signals maybe used for channel estimation, cell selection and reselection, handoverprocedures and the like.

In 3GPP a Study Item (SI) on New Radio Access Technology (NR) has beenagreed, as can exemplary be taken from 3GPP document RP-160671, “New SIDProposal: Study on New Radio Access Technology,” NTT DOCOMO, RAN #71. Onthe basis of this SI a new Radio Access Technology (RAT) for the nextgeneration wireless communications system, i.e. 5G, is studied anddeveloped. The new RAT is expected to operate in a wide range offrequencies, in some embodiments, for example, from hundreds of MHz toone hundred GHz and it is expected to cover a broad range of use casesin some embodiments.

Typical use cases that may be considered, e.g. under this SI, areEnhanced Mobile Broadband (eMBB), Massive Machine Type Communications(mMTC), and Ultra Reliable & Low Latency Communications (URLLC).

Typically, for any waking user equipment (UE) accessing a network (e.g.LTE and/or NR network), detecting the primary and secondarysynchronization signals (PSS and SSS) provides the UE, for example, withtime, frequency and frame synchronization as well as sector, group andcell identity information. Following this, the UE can then find anddecode the physical broadcast channel (PBCH), which in turn provides theUE with critical system and configuration information of the particularcomponent carrier. This critical system and configuration information issometimes referred to as a “Master Information Block”, MIB. Whilst thedetection of the PSS and SSS entails the processing of signals to detectthe random sequences used in their construction, decoding of the PBCHactually entails the channel estimation and equalization, demodulationand forward error correction code decoding of critical systeminformation bits carried by the PBCH.

The PSS and SSS are therefore, in some embodiments, designed to bedetectable non-coherently, i.e. in the presence of unknown timing andfrequency offsets, whether the UE is stationary or moving. Often, inpractice, the PSS is detected first and its processing may provideenough frequency and timing offset correction to allow the subsequentdetection of the SSS to be done coherently. The PBCH on the other handmust be decoded coherently. This may mean that apart from the fact thatthis is done after frequency and timing offset correction, the channelmay, or even must, be estimated and equalized before the set of resourceelements carrying the critical system information can be demodulated anddecoded. Mobile systems may suffer from time and frequency selectivity.Channel estimation therefore may have to contend with thesedegradations. The time selectivity of the radio channel is due totime-varying fading that arises from relative movement between the UEand the base station, e.g. eNodeB. This time selectivity can bequantified as the coherence time of the transmission channel or Dopplerspread which depends on the relative speed of movement between the UEand the base station, e.g. eNodeB. For these reasons, the OFDM symbolscarrying the PBCH must be resilient to Doppler spread in someembodiments. OFDM symbol resilience to Doppler spread may be assured bywider subcarrier spacing (SCS) between the subcarriers of the OFDMsymbol.

It is known that at higher operating frequencies, a given speed oftravel for the UE results in a higher Doppler spread than would be thecase for operation at a lower frequency band. The RAN1 3GPP group hasdecided that the SCS to be used for OFDM symbols carrying the PSS andSSS will be determined according to the operating frequency range forthis reason. This may also be implemented in some embodiments.Nevertheless, for networks operating at higher frequency bands, it maybe desirable to use a narrower SCS for the PSS and SSS, as this may maketime domain detection of the PSS easier at the UE. In such an operatingscenario, it may be desirable in some embodiments, for the PBCH to becarried on OFDM symbols with wider subcarrier spacing in order to ensureits robustness to Doppler spread.

Hence, some embodiments provide an efficient means of conveying to thereceiver the SCS of the PBCH OFDM symbols, pertain to the issue of howthe wider subcarrier spacing of the PBCH symbols can be derived from theSCS of the synchronization symbols in a manner to make its signalingeasier, and provide alternative means of carrying the critical systeminformation of the PBCH OFDM symbols even if they use the SCS of thesynchronization symbols but in a manner more robust to Doppler spread.

Consequently, some embodiments pertain to a base station, a userequipment and a mobile telecommunications system method, as will also bediscussed in the following. The base station and the user equipment eachhave a circuitry which is configured to perform a method and the mobiletelecommunications system method may include the methods as performed bythe circuitry of the user equipment and of the base station.

The base station may be based on the principles of LTE (LTE-A) and/or itmay be based on NR RAT, as also discussed above. The base station may bebased on the known eNodeB of LTE, as one example, or it may be based onthe discussed NR eNodeB. The user equipment may be, for example, amobile phone, smartphone, a computer, tablet, tablet personal computer,or the like, including a mobile communication interface, or any otherdevice which is able to perform a mobile telecommunication via, forexample, LTE or NR, such as a hot spot device with a mobilecommunication interface, etc.

Some embodiments pertain to a base station for a mobiletelecommunications system comprising circuitry configured to communicatewith at least one user equipment, wherein the circuitry is furtherconfigured to set a first subcarrier spacing for transmission of atleast one synchronization signal; and set a second subcarrier spacingfor transmission on a physical broadcast channel, wherein the firstsubcarrier spacing differs from the second subcarrier spacing. Thesynchronization signal may be a primary synchronization signal or asecondary synchronization signal. As mentioned, the transmission may bebased, as discussed, on the LTE standard or on a successor. Hence, insome embodiments, a different SCS can be used for synchronizationsignals (PSS & SSS) and PBCH transmission.

Corresponding embodiments pertain to a user equipment for a mobiletelecommunications system comprising circuitry configured to communicatewith at least one base station, wherein the circuitry is furtherconfigured to receive at least one synchronization signal and receive atransmission over a physical broadcast channel, wherein thesynchronization signal is transmitted with a first subcarrier spacingand the transmission over the physical broadcast channel is transmittedwith a second subcarrier spacing, wherein the first subcarrier spacingdiffers from the second subcarrier spacing.

Some embodiments pertain to a base station for a mobiletelecommunications system comprising circuitry configured to communicatewith at least one user equipment, wherein the circuitry is furtherconfigured to indicate, based on a primary synchronization signal, aspecific subcarrier spacing for a physical broadcast channel. Hence,some embodiments allow using PSS to signal which SCS is used for PBCH ingeneral and, for example, provide a method of encoding and transmittingthat signaling by toggling signs of PSS sequence on both halves of itsspectrum.

The primary synchronization signal may include a symbol sequence, as itis generally known, and it may be based on transmission of OFDM symbols.

The symbol sequence may be divided in at least two parts and thespecific subcarrier spacing may be indicated, based on the division ofthe symbol sequence. For example, for each part of the divided symbolsequence, a positive or negative sign may be assigned and the specificsubcarrier spacing may be indicated, based on the signs assigned to theparts, as will also be discussed further below. Each part of the dividedsymbol sequence may be multiplied by the sign assigned to the part. Theamount of the specific subcarrier spacing may depend on the number ofparts into which the symbol sequence, i.e. the primary synchronizationsignal is divided and/or the relationship between the amount of thespecific subcarrier spacing used on the physical broadcast channel andthe number of parts into which symbol sequence is divided may bepredefined.

Corresponding embodiments pertain to a user equipment for a mobiletelecommunications system comprising circuitry configured to communicatewith at least one base station, wherein the circuitry is furtherconfigured to receive at least one primary synchronization signal; andto determine, based on the received at least one primary synchronizationsignal, a subcarrier spacing of a physical broadcast channel. Hence,some embodiments, allow reducing complexity at a receiver side to allowdetection of the PBCH SCS signaling on the PSS. As mentioned, theprimary synchronization signal may include a symbol sequence, and thesymbol sequence may be divided in at least two parts, and the specificsubcarrier spacing is determined based on the division of the symbolsequence. For each part of the divided symbol sequence, a positive ornegative sign may be assigned and the subcarrier spacing may bedetermined, based on the signs assigned to the parts. As also discussed,the amount of the subcarrier spacing may depend on the number of partsand/or the amount of the subcarrier spacing may be predefined. Thecircuitry may be further configured to compute a correlation betweenparts of the received primary synchronization signal. Thereby, inparticular, when a positive/negative sign is assigned to the parts ofthe primary synchronization signal, the search for subcarrier spacing isreduced, basically, to a sign search.

Some embodiments pertain to a base station for a mobiletelecommunications system comprising circuitry configured to communicatewith at least one user equipment, wherein the circuitry is furtherconfigured to transmit symbols on a physical broadcast channel, whereinsymbols are transmitted with (at least) a (first) subcarrier spacing andmodulation symbols are repeated in consecutive resource elements in thefrequency domain. Although, in some embodiments PBCH symbols aretransmitted at one subcarrier spacing in our special repeated pattern,which may have the effect of providing the resilience of a widersubcarrier spacing, in some embodiments, the symbols may be transmittedwith different subcarrier spacings. Hence, in some embodiments, anincreasing of the SCS of PBCH is provided by repetition of QAM symbolsover REs (resource elements). For example, if a base SCS is 15 kHz arepetition of symbols of four times results in an effective SCS of 60kHz. Thereby, a guard band which may be needed in known systems, can bemade obsolete. The symbols may include quadrature amplitude modulationsymbols.

Corresponding embodiments pertain to a user equipment for a mobiletelecommunications system comprising circuitry configured to communicatewith at least one base station, wherein the circuitry is furtherconfigured to receive symbols on a physical broadcast channel, whereinsymbols are transmitted with (at least) a (first) subcarrier spacing andmodulation symbols are repeated in consecutive resource elements in thefrequency domain. As mentioned, the symbols may include quadratureamplitude modulation symbols. The receiving of symbols may includedecoding the repeatedly transmitted symbol based on the first subcarrierspacing and/or the receiving of the symbols may include decoding therepeatedly transmitted symbol based on a second subcarrier spacing.Hence, in some embodiments, the receiver approach in decoding suchrepeated QAM symbols either uses the base SCS and then combines theresult prior to demodulation (where the process of demodulation includesthe generation of log-likelihood rations in some exemplary embodiments)or it uses decoding with the composite and larger SCS.

Some embodiments pertain to a base station for a mobiletelecommunications system comprising circuitry configured to communicatewith at least one user equipment, wherein the circuitry is furtherconfigured to transmit symbols in a physical broadcast channel byapplying a phase ramp, as will also be discussed further below. Hence,some embodiments allow carrying PBCH in a more robust manner byexploiting processing gain instead of FEC coding, this may reduce thenumber of bits to be transmitted allowing more compact transmission.Each burst of the physical broadcast channel may include a referencesymbol. The reference symbol may be based on a Zadoff-Chu sequence. Aroot of the Zadoff-Chu sequence may differ from a root of a Zadoff-Chusequence used for a primary synchronization signal. The phase ramp maybe based on a phase shift applied to a previous symbol. The phase shiftmay be spread over 2π.

Corresponding embodiments pertain to a user equipment for a mobiletelecommunications system comprising circuitry configured to communicatewith at least one base station, wherein the circuitry is furtherconfigured to receive symbols over a physical broadcast channel, whereina phase ramp is applied to at least one symbol and the bursts of thephysical broadcast channel are repeated once. Hence, some embodimentsprovide a receiving side including decoding the phase shifts, CRCchecking, potentially exiting after the first two bursts if the CRCpasses, and if the CRC fails storing and combining results prior to IFFTand peak detection and CRC checking a second time. The phase ramp may beestimated on at least one symbol of a burst of the physical broadcastchannel and a burst reference sequence. The phase ramp may be detectedbased on an inverse discrete Fourier transformation.

All embodiments disclosed herein can be combined, such that, for examplealso embodiments exist where a base station implements all or anysub-combination of base station features as described herein and a userequipment implements all or any sub-combination of user equipmentfeatures as described herein.

Returning to FIG. 1, there is illustrated a RAN 1 which has a macro cell2, which is established by a LTE eNodeB 3, and a NR cell 4, which isestablished by a NR eNodeB 5.

A UE 6 can communicate with the LTE eNodeB 3 and, as long it is withinthe NR cell 4, it can also communicate with the NR eNodeB 5. Asmentioned above, for example, when the UE 6 wakes up, it may search forthe primary and secondary synchronization signals.

Although the communication according to LTE is generally known, FIG. 2schematically and exemplary illustrates an FDD (Frequency DivisionDuplexing) frame 10 which has a length of 10 ms. Each vertical linecorresponds to one slot 11 and two slots form a subframe 12. One slotincludes in this example six resource blocks, wherein one resource block13 is depicted on the right side of the frame 10.

Each resource block is divided into twelve subcarriers 14, wherein eachof the subcarriers 14 is carried on seven OFDM symbols 15. The PBCH maybe located in a different slot of the same subframe, e.g. in the nextslot following slot 11.

As mentioned above, in LTE, the PSS is located in the last OFDM(Orthogonal Frequency-Division Multiplexing) symbol of the first timeslot of the first subframe (subframe 0) of a radio frame, such as radioframe 10. In frame 10, the first time slot is time slot 11 in the firstsubframe 12, i.e. the most left vertical structure of six resourceblocks. In a first step, the UE decodes the primary synchronizationsignal (PSS). In a next step, typically, the UE finds the secondarysynchronization signal (SSS), wherein the symbols of the SSS are locatedin the same subframe as the symbols of the PSS.

In LTE-A, the PSS is composed of one of three sequences. Detecting anyone of these sequences at the UE, e.g. UE 6, indicates that thecomponent carrier is transmitted from one of three possible sectors ofthe (NR) eNodeB, e.g. eNodeB 5. The SSS on the other hand carries two 31element sequences which can be arranged in one of 168 possible ways.Between the PSS and SSS can therefore be signaled 504 different cellidentities ranging from 0 to 3*167+2=503.

In the following, an embodiment pertaining to signaling the SCS by useof the PSS is discussed under reference of FIG. 3, which is a flowchartof a mobile telecommunications method 30 which can be performed by a(NR) base station, such as eNodeB 5 and a user equipment, such as UE 6.Moreover, the SCS of the PSS and of the PBCH may differ from each other,as will be discussed below.

In this embodiment, the PSS is structured to also convey information ofthe SCS that will be used for the PBCH for indicating which amount ofSCS is used. Here, the used PSS sequence is exemplary divided at 31,e.g. by the eNodeB, into two halves (in other embodiments it could bedivided into more parts).

Let the basic sequence used for the PSS be designated as {umlaut over(Z)}_(i)(n) n=0, 1, . . . , N and i∈{0,1,2} then the modified used PSSsequence Z_(i)(n) would be:

${Z_{i}(n)} = \left\{ \begin{matrix}{S_{L}*{{\overset{¨}{Z}}_{i}(n)}} & {{{for}\mspace{14mu} n}\  \leq \frac{N}{2}} \\0 & {{{for}\mspace{14mu} n} = \left\lceil \frac{\left( {N + 1} \right)}{2} \right\rceil} \\{S_{H}*{{\overset{¨}{Z}}_{i}(n)}} & {{{for}\mspace{14mu} n} > \left\lceil \frac{\left( {N + 1} \right)}{2} \right\rceil}\end{matrix} \right.$

Where (N+1) (often odd) is the length of the sequence. In LTE, N=62.

With the binary variables S_(L) and S_(H), at least 4 different SCS forthe PBCH symbols can be signaled as in Table 1, whereby at 32 the SCSmay be indicated, e.g. by the eNodeB 5. Hence, for each half and theassociated SCS used in the PBCH, a sign is assigned at 32 for indicatingthe SCS.

TABLE 1 Example settings for signaling of PBCH subcarrier spacing S_(L)S_(H) PBCH SCS, a 1 1 0 1 −1 1 −1 1 2 −1 −1 3

The entry a in the PBCH SCS column of Table 1 may be a scale factor suchthat the SCS of the PBCH OFDM symbols is 2^(a) (i.e. 2{circumflex over( )}a) times the SCS of the OFDM symbol carrying the PSS. Therefore,when a=0, the SCS of the PBCH OFDM symbols is the same as that of theOFDM symbol carrying the PSS. In another embodiment, a could be theindex to a table of SCS values, such that thereby the SCS used can beindicated at 32. The table may directly include SCS values or it mayeven point to another table, or it may include a formula for calculatingSCS values, etc.

This approach might be seen as increasing the number of sequences tosearch through at the UE by a factor of four, thereby quadrupling theamount of processing for PSS detection. However, because the SCSsignaling is only carried in the sign of halves of the original PSSsequence, the processing complexity can be considerably reduced bycomputing the correlation with the original sequence Z_(i)(n) in twohalves at the UE receiving side at 33. Assuming the received sequence isR(n), then the half-correlations for a given index k is:

${X_{L}(k)} = {\sum\limits_{n = 0}^{\frac{N}{2}}{{Z_{i}(n)}*{R^{*}\left( {n + k} \right)}}}$${X_{H}(k)} = {\sum\limits_{n = {\lceil\frac{({N + 1})}{2}\rceil}}^{N}{{Z_{i}(n)}*{R^{*}\left( {n + k} \right)}}}$

Then to find the correlation for the various entries in Table 1, thedifferent correlation results X(k) are derived as illustrated in Table2.

TABLE 2 Computation of correlation results related to PBCH SCS signalingS_(L) S_(H) X(k) 1 1 |X_(L)(k) + X_(H)(k)| 1 −1 |X_(L)(k) − X_(H)(k)| −11 |−X_(L)(k) + X_(H)(k)|  −1 −1 |−X_(L)(k) − X_(H)(k)| 

The sign search therefore entails only toggling of the signs of eachhalf correlation systematically before summing up the results, which maybe a miniscule change in complexity in some embodiments. Based, on thesigns found in the sign search, the UE 6 determines the SCS at 34.

As mentioned, the disclosure is not restricted to signal only four SCS,any other number of SCS can also be signaled using this method, e.g. bydividing the PSS sequence in more than two parts.

In the following, an embodiment pertaining to the implicit scaling ofthe PBCH SCS is discussed under reference of FIGS. 4 and 5. FIG. 4 is aflowchart of a mobile telecommunications method 40 which can beperformed by a base station, such as eNodeB 5 and a user equipment, suchas UE 6. FIG. 5 illustrates subcarrier scaling by QAM symbol repetition.

The SCS used for the payload data (i.e. data transmitted on PDSCH, whichis transmitted, for example in the first subframe in one or both slots)can differ between subframes or slots of the same component carrier orbetween base stations of the same PLMN (Public Land Mobile Network).

In an exemplary embodiment, the subcarrier spacings that can be used arepower of two multiples of each other, while in other embodiments, asdiscussed above, the OFDM symbols are repeated by a specific (integer)number, e.g. three times, which may result in a 45 kHz SCS, if the baseSCS is 15 kHz, or five times, which may result in a 75 kHz SCS, if thebase SCS is 15 kHz (without limiting the present disclosure to theseexamples). The PBCH is not expected to use all the resource elements(RE) in each of the OFDM symbols it is carried on. Therefore, the PBCHcarrying OFDM symbols has to carry payload (PDSCH) or other signals onthe same OFDM symbol. If the PBCH is to use for data transmission at 41by e.g. eNodeB 5 a wider SCS than the rest of the data that shares itsOFDM symbols and the PBCH REs use a different SCS than the other REs ofthe same OFDM symbol, then there may be need for guard bands separatingthe zones of differing SCS in order to avoid interference arising fromthe differences in SCS.

The present embodiment provides a solution where a guard band may be notneeded and, therefore, may be obsolete by repeating adjacent resourceelements in the PBCH carrying REs, performed at 42, e.g. by eNodeB 5.Therefore, for PBCH SCS of a in Table 1, each PBCH QAM symbol would bemapped to 2^(a) (i.e. 2{circumflex over ( )}a) adjacent REs. This isillustrated for a=0,1,2,3 in FIG. 5.

In each vertical grid, the grey lines indicate repetition boundarieswhile the black lines indicate change of a QAM symbol, such that for a=0no repetition is present, for a=1 two repetitions, for a=2 fourrepetitions and for a=3 eight repetitions. Transmitted with thisarrangement, each PBCH carrying OFDM symbol can be equalized as a signalwith SCS corresponding to a=0 in which case, after equalization the REscarrying repetitions of the same QAM symbol should be maximal ratiocombined prior to QAM de-mapping. The PBCH carrying OFDM symbol can alsobe equalized as a signal with SCS=2^(a) (i.e. 2{circumflex over ( )}a)to avoid the maximal ratio combining and increase resilience to Dopplerspread.

For a fixed number of bits in the PBCH this repetition reduces the PBCHcarrying capacity of each OFDM symbol by a factor of 2a (i.e.2{circumflex over ( )}-a). It therefore follows that for the samebandwidth, the number of OFDM symbols required to carry the PBCH wouldincrease by a factor of 2^(a) (i.e. 2{circumflex over ( )}a). On theother hand, since it is possible to think of the REs as having abandwidth of 2^(a) (i.e. 2{circumflex over ( )}a) times the basic SCS,assigning the same number of these wider REs per OFDM symbol to carrythe PBCH as before requires that the raw bandwidth allocated for PBCHshould increase to 2^(a) (i.e. 2{circumflex over ( )}a) times what itwas with the basic SCS. In this embodiment, the number of OFDM symbolsnecessary to carry one PBCH remains the same as before repetition.

When this repetition approach is taken, then the reference symbols usedfor demodulating the PBCH at 43 have to be similarly repeated ordistributed at 44 taking into account the 2^(a) (i.e. 2{circumflex over( )}a) scaling of the SCS, wherein this is performed e.g. by UE 6.Alternatively, the PBCH can be decoded using the PSS and/or SSS asreference symbols, in which case there is no need for reference symbolswithin the PBCH structure.

Despite the above analysis comparing repetition versus non-repetition,it should be understood that in Rel 13 of LTE, the PBCH transmits 40bits (24 bits+16 CRC bits). These bits are coded with a combination ofan actual 1/3-rate code and repetition coding to an aggregate code rateof 1/48 giving a total of 1920 bits for the output block size. Thisblock is then broken up into 4 bursts each of 480 bits, each to bemodulated by QPSK modulation and transmitted in a subframe using 240REs.

Using this disclosure to increase the SCS by 2^(a) (i.e. 2{circumflexover ( )}a) for the PBCH OFDM symbols, as discussed above, therepetition code rate can be proportionally increased to 2^(a)/48 in someembodiments. For example, let a=3 so that 2^(a)=8. Then the effectiveaggregate code rate can be increased to 8/48=1/6 i.e. after the 1/3-ratecode, a repetition code rate of 2 is applied, instead of 1/16 as before.The PBCH output coded block size is now 40*6=240 bits. As in Rel-14 ofLTE, this is divided into 4 equal bursts each of 60 bits modulated into30 QPSK symbols. A SCS=2^(a) entails repeating each QPSK symbol over 8adjacent REs. Thus the 30 QPSK symbols of each burst would still occupy30*8=240 REs in the subframe as before. Therefore, there is no overallincrease in required REs. However, in some embodiments, there is someloss of coding gain because of the higher aggregate code rate. This ismore than made up for by the diversity gain arising from repeating eachQPSK symbol 8 times. Thus, the PBCH still occupies 480 physicalbits/subframe (and still occupies 1.08 MHz with SCS=15 kHz and the timetaken to transmit 4 subframes).

In the following, an embodiment pertaining to a more robust method tocarry the PBCH in OFDM symbols of smaller SCS is discussed underreference of FIGS. 6 and 7. FIG. 6 is a flowchart of a mobiletelecommunications method 50 which can be performed by a base station,such as eNodeB 5 and a user equipment, such as UE 6. FIG. 7schematically illustrates a receiver of a UE, such as UE 6.

The repetition of QAM symbols on adjacent REs, as discussed above, mayhave, in some embodiments, the deleterious effect of either requiring anincrease in the number of OFDM symbols carrying the PBCH or increasingthe raw bandwidth of the PBCH.

Increasing the raw bandwidth may not be feasible if the expected rawbandwidth exceeds the component carrier bandwidth. The increasedbandwidth may also result in an increase in power consumption for the UEbecause of the wider bandwidth to be tuned.

On the other hand, if the raw bandwidth is kept constant and the numberof OFDM symbols is increased instead, this increase in the number ofsymbols results in delay in decoding of the PBCH.

It is therefore desirable, in some embodiments, to minimize as much aspossible the factor 2^(a) (i.e. 2{circumflex over ( )}a) as thisminimizes either the required increase in bandwidth or number of OFDMsymbols. It may still be desirable to have 2^(a)>1 (wider SCS for thePBCH), but if the PBCH information can be carried more robustly, thefactor 2^(a) may be set to 2 or 4 instead of 8. This would reduce thenecessary bandwidth or number of PBCH carrying symbols significantly insome embodiments.

In LTE-A, the PBCH after CRC protection is made up of 40 bits beforeerror control coding is applied to it. By substituting processing gainfor coding gain, the FEC coding of the PBCH can be dispensed with. The40 bit PBCH is split into eight fields each of five bits long. Eachburst of PBCH bearing OFDM symbols is comprised of five OFDM symbols,the first being a burst reference symbol, whose REs align with those ofthe following four burst PBCH symbols. The reference symbol carries aburst reference sequence in the REs reserved for the PBCH.

In an embodiment, the burst reference sequence is a particularZadoff-Chu (ZC) sequence, which is generally known, with a differentroot than the sequences used for the PSS. In another embodiment, thechosen ZC sequence is also multiplied by an N chip m-sequence to improveits autocorrelation properties (in LTE Rel-14, N=62).

Each of the following four PBCH symbols of the burst carries one of thePBCH fields by applying a calculated phase ramp at 51, e.g. by theeNodeB 5, to each of the REs of a copy of the burst reference symbol.The phase ramp to apply is calculated from the sum of the decimal valueof the five bits PBCH field and the phase shift applied to the previoussymbol. Since each burst carries only four PBCH fields, it thereforetakes two PBCH bursts at 52, e.g. performed by the eNodeB 5, to carryall the eight fields of the PBCH. In LTE-A, the PBCH is carried overfour bursts (one burst is transmitted per radio frame over a period of40 ms). Equivalently, in an embodiment of this case, the two burstscarrying all the fields of the PBCH are repeated at 53, e.g. performedby the eNodeB 5, once per 40 ms period (e.g. the first burst istransmitted in the first and third radio frames of a 40 ms period andthe second burst is transmitted in the second and fourth radio frames ofthe 40 ms period).

In one embodiment, the relative phase shift M₀ applied to the referencesymbol is substantially zero but can be some other fixed and knownvalue. Then the sequence for the REs of PBCH burst symbol n will be:

S _(n)(k)=Z(k)*e ^(j2πk(M) ^(n-1) ^(+ƒ(D) ^(n) ^())/N) ^(FFT)

M _(n)=(M _(n-1)+ƒ(D _(n)))mod N _(FFT)

For n=1, 2, 3, 4 and where D_(n) (i.e. D_n) is the decimal value of the5-bits field allocated for transmission in symbol n, Z(k) is the burstreference symbol sequence and N_(F) is the size of the DFT used forconverting the PBCH time domain symbol into the frequency domain. With0≤D_(n)≤31, there are therefore only 32 possible valid phase shifts thatcan be applied to the reference sequence. However, the referencesequence has length N_(FFT) which is more than 32. This means thequantization of the phase shifts can be significantly coarser. This isdone by use of the function ƒ(·) (“·” being a placeholder) on thedecimal value of the PBCH field. The effect of this function is tospread the possible phase shifts uniformly over 2π. The function ƒ(·)therefore converts the number 0≤D_(n)≤31 to a number 0≤ƒ(D)≤N_(FFT)where in general, D_(n)≤N_(FFT).

At the receiver, e.g. performed by the UE 6, the phase ramps can beestimated at 54 without explicit channel estimation and correction sincethe UE knows the symbols of the PBCH burst and the burst referencesequence Z(k).

Thus for the sequence of the REs of the PBCH burst symbol n and assumingthe received resource elements are R_(n)(k) and that the channel H(k) isrelatively stationary between symbols n−1 and n, the UE can compute(ignoring the index k, “.” is an abbreviation for a (dot) product):

R _(n-1) R* _(n)=(H·Z·e ^(−2πM) ^(n-1) ^(/N) ^(FFT) +N _(n-1))*(H·Z·e^(−j2π(M) ^(n-1) ^(+ƒ(D) ^(n) ^())/N) ^(FFT) +N _(n))*

Where N_(n) is the noise on symbol n. This can be expanded as follows:

R _(n-1) R* _(n) =|H| ² |Z| ₂ e ^(j2πƒ(D) ^(n) ^()/N) ^(FFT) +H·Z·e^(−jα) ·N _(n) *+H*·Z*·e−jβ·N _(n-1) +N _(n-1) ·N _(n)*

where β=2π(M_(n-1)+ƒ(D_(n)))/N_(FFT) and α=2πM_(n-1)/N_(FFT).

The second and third terms of the right-hand side are modulated noisewhilst the last term is just plain white noise. As all the noise isadditive, the combined power of these terms depends on the SNR of thereceived signal. It can therefore be expected in some embodiments that,at reasonable levels of SNR, the argument or phase trajectory of theresult would be dominated by the first term on the right. Thus bydetecting the phase slope of the result, ƒ(D_(n)) can be detected, i.e.the relative phase ramp between the two symbols. Further, this phaseramp can also be detected by carrying out an IDFT at 55 on the resultand taking the sample location of the peak amplitude since:

IFFT(e ^(−j2πnk/N) ^(FFT) )=FFT(e ^(j2πnk/N) ^(FFT) )/N _(FFT)

Where, for example (as, e.g. also in LTE), N_(FFT)=64. The actualdecimal number D_(n) can then be found by passing the detected samplelocation through the inverse function ƒ¹(·).

Taking LTE as an example in which N_(FFT)=64, an example function ƒ(·)for spreading all the possible phase shifts uniformly from 0 to 2π couldbe:

ƒ(n)=2*n→ƒ ⁻¹(n)=n/2

In other embodiments ƒ(n) can also take into account the known Graycoding such that any two possible phase shifts that are close in valueto each other are derived from values of n that only differ by one bit.

A functional receiver algorithm 60, as may be implemented in UE 6, whichmay perform the receiving steps discussed above, is illustrated in FIG.7. The algorithm 60 has a “Delay N_(u)” part 61, a first FFT (FastFourier Transform) part 62 and a second FFT part 63, a conjugate part64, an IFFT (inverse FFT) part 65, and a peak detection function part66, where N_(u) (i.e. N_u) in the “Delay N_(u)” part 61 is the number oftime domain samples in one OFDM symbol (excluding the cyclic prefix) andthe input r_(n)(i) (i.e. r_n(i)) is assumed to be already stripped ofthe cyclic prefixes.

The input r_(n)(i) (i.e. r_n(i)) is split into a first part and a secondpart. The first part is delayed by part 61, while the second part isinput into the second FFT 63 and the conjugate part 64 calculates theconjugate of the output of FFT 63. After delaying the first part, it isinput into FFT 62 and the output of FFT 62 is multiplied at 67 with theoutput of 64. The multiplied output is fed to IFFT part 65 (moregenerally an IDFT) which calculates the IFFT, as discussed above. Theoutput of 65 is fed to part 66, which performs peak detection of theoutput of the IFFT and calculates the inverse function of the input,whereby the D_(n) can be derived.

In an embodiment where the two bursts carrying all the fields of thePBCH are repeated once, each PBCH field is transmitted twice. This meansthe CRC can be checked after decoding all fields at the end of thesecond PBCH burst. If the CRC passes, PBCH decoding can be said to havesucceeded and the remaining two bursts can then be ignored. Otherwise,the third and fourth bursts are also received, decoded and the CRCchecked again. It is expected, in some embodiments, that one of the CRCspasses.

In another embodiment of the receiver (for the case where the two burstscarrying all the fields of the PBCH are repeated once and hence eachPBCH field is transmitted twice), the outputs of the multiplier 67 inFIG. 7 for each of the PBCH fields carrying symbols can be storedseparately during reception of the first two bursts. Then duringreception of the third and fourth bursts, the output of the multiplier67 can be combined with that of the equivalent symbols previously storedfrom the first two bursts and the result of this combiner passed throughthe IFFT and peak detection. The diversity combining improves thereliability of the detected phase slopes.

In some embodiments, carrying of information in a pre-processing of aknown sequence carried on an OFDM symbol is known and used for theATSC3.0 bootstrap signal. In that case, the values are carried in atime-domain cyclic shift of a whole OFDM symbol. In this case, we arecarrying the information in a phase ramp restricted to the resourceelements allocated for the PBCH. All other resource elements of thesymbol are left unchanged.

As mentioned above, embodiments may be combined. For example, in someembodiments, the embodiments of FIGS. 1 to 7 are combined. Also theembodiments of FIGS. 3 to 7 may be combined, or the embodiments of FIGS.3 and 6 to 7, or the embodiments of FIGS. 3 and 4 to 5, etc. Someembodiments may pertain to a combination of the embodiments of FIGS. 4to 7. In particular, in some embodiments, the methods 30, 40 and 50 arecombined to one method, or the methods 30 and 40 are combined to onemethod, or the methods 30 and 50 are combined to one method. Someembodiments may pertain to a combination of methods 40 and 50.

In the following, an embodiment of a general purpose computer 130 isdescribed under reference of FIG. 8. The computer 130 can be implementedsuch that it can basically function as any type of base station or newradio base station, transmission and reception point, or user equipmentas described herein. The computer has components 131 to 140, which canform a circuitry, such as any one of the circuitries of the basestations, and user equipments, as described herein.

Embodiments which use software, firmware, programs or the like forperforming the methods as described herein can be installed on computer130, which is then configured to be suitable for the concreteembodiment.

The computer 130 has a CPU 131 (Central Processing Unit), which canexecute various types of procedures and methods as described herein, forexample, in accordance with programs stored in a read-only memory (ROM)132, stored in a storage 137 and loaded into a random access memory(RAM) 133, stored on a medium 140 which can be inserted in a respectivedrive 139, etc.

The CPU 131, the ROM 132 and the RAM 133 are connected with a bus 141,which in turn is connected to an input/output interface 134. The numberof CPUs, memories and storages is only exemplary, and the skilled personwill appreciate that the computer 130 can be adapted and configuredaccordingly for meeting specific requirements which arise, when itfunctions as a base station, and user equipment.

At the input/output interface 134 several components are connected: aninput 135, an output 136, the storage 137, a communication interface 138and the drive 139, into which a medium 140 (compact disc, digital videodisc, compact flash memory, or the like) can be inserted.

The input 135 can be a pointer device (mouse, graphic table, or thelike), a keyboard, a microphone, a camera, a touchscreen, etc.

The output 136 can have a display (liquid crystal display, cathode raytube display, light emittance diode display, etc.), loudspeakers, etc.

The storage 137 can have a hard disk, a solid state drive and the like.

The communication interface 138 can be adapted to communicate, forexample, via a local area network (LAN), wireless local area network(WLAN), mobile telecommunications system (GSM, UMTS, LTE, NR etc.),Bluetooth, infrared, etc.

It should be noted that the description above only pertains to anexample configuration of computer 130. Alternative configurations may beimplemented with additional or other sensors, storage devices,interfaces or the like. For example, the communication interface 138 maysupport other radio access technologies than the mentioned UMTS, LTE andNR.

When the computer 130 functions as a base station, the communicationinterface 138 can further have a respective air interface (providinge.g. E-UTRA protocols OFDMA (downlink) and SC-FDMA (uplink)) and networkinterfaces (implementing for example protocols such as S1-AP, GTP-U,S1-MME, X2-AP, or the like). Moreover, the computer 130 may have one ormore antennas and/or an antenna array. The present disclosure is notlimited to any particularities of such protocols.

The methods as described herein are also implemented in some embodimentsas a computer program causing a computer and/or a processor and/orcircuitry to perform the method, when being carried out on the computerand/or processor and/or circuitry. In some embodiments, also anon-transitory computer-readable recording medium is provided thatstores therein a computer program product, which, when executed by aprocessor and/or circuitry, such as the processor and/or circuitrydescribed above, causes the methods described herein to be performed.

It should be recognized that the embodiments describe methods with anexemplary order of method steps. The specific order of method steps is,however, given for illustrative purposes only and should not beconstrued as binding.

All units and entities described in this specification and claimed inthe appended claims can, if not stated otherwise, be implemented asintegrated circuit logic, for example on a chip, and functionalityprovided by such units and entities can, if not stated otherwise, beimplemented by software.

In so far as the embodiments of the disclosure described above areimplemented, at least in part, using a software-controlled dataprocessing apparatus, it will be appreciated that a computer programproviding such software control and a transmission, storage or othermedium by which such a computer program is provided are envisaged asaspects of the present disclosure.

Note that the present technology can also be configured as describedbelow.

(1) A base station for a mobile telecommunications system comprisingcircuitry configured to communicate with at least one user equipment,wherein the circuitry is further configured to:

-   -   set a first subcarrier spacing for transmission of at least one        synchronization signal; and    -   set a second subcarrier spacing for transmission on a physical        broadcast channel, wherein the first subcarrier spacing differs        from the second subcarrier spacing.

(2) The base station of (1), wherein the synchronization signal is aprimary synchronization signal or a secondary synchronization signal.

(3) A user equipment for a mobile telecommunications system comprisingcircuitry configured to communicate with at least one base station,wherein the circuitry is further configured to:

-   -   receive at least one synchronization signal and receive a        transmission over a physical broadcast channel, wherein the        synchronization signal is transmitted with a first subcarrier        spacing and the transmission over the physical broadcast channel        is transmitted with a second subcarrier spacing, wherein the        first subcarrier spacing differs from the second subcarrier        spacing.

(4) A base station for a mobile telecommunications system comprisingcircuitry configured to communicate with at least one user equipment,wherein the circuitry is further configured to:

-   -   indicate, based on a primary synchronization signal, a specific        subcarrier spacing for a physical broadcast channel.

(5) The base station of (4), wherein the primary synchronization signalincludes a symbol sequence.

(6) The base station of (5), wherein the symbol sequence is divided inat least two parts and the specific subcarrier spacing is indicated,based on the division of the symbol sequence.

(7) The base station of (6), wherein for each part of the divided symbolsequence, a positive or negative sign is assigned.

(8) The base station of (7), wherein the specific subcarrier spacing isindicated, based on the signs assigned to the parts.

(9) The base station of anyone of (6) to (8), wherein the amount of thespecific subcarrier spacing depends on the number of parts.

(10) The base station of (9), wherein the amount of the specificsubcarrier spacing of the physical broadcast channel and the number ofparts into which the symbol sequence is divided is predefined.

(11) A user equipment for a mobile telecommunications system comprisingcircuitry configured to communicate with at least one base station,wherein the circuitry is further configured to:

-   -   receive at least one primary synchronization signal; and    -   determine based on the received at least one primary        synchronization signal a subcarrier spacing of a physical        broadcast channel.

(12) The user equipment of (11), wherein the primary synchronizationsignal includes a symbol sequence.

(13) The user equipment of (12), wherein the symbol sequence is dividedin at least two parts and the specific subcarrier spacing is determinedbased on the division of the symbol sequence.

(14) The user equipment of (13), wherein for each part of the dividedsymbol sequence, a positive or negative sign is assigned.

(15) The user equipment of (14), wherein the specific subcarrier spacingis determined, based on the signs assigned to the parts.

(16) The user equipment of anyone of (13) to (15), wherein the amount ofthe specific subcarrier spacing depends on the number of parts.

(17) The user equipment of (16), wherein the amount of the specificsubcarrier spacing of the physical broadcast channel and the number ofparts into which the symbol sequence is divided is predefined.

(18) The user equipment of anyone of (13) to (17), further comprisingcomputing a correlation between parts of the received primarysynchronization signal.

(19) A base station for a mobile telecommunications system comprisingcircuitry configured to communicate with at least one user equipment,wherein the circuitry is further configured to:

-   -   transmit symbols on a physical broadcast channel, wherein        symbols are transmitted with a subcarrier spacing and modulation        symbols are repeated in consecutive resource elements in the        frequency domain.

(20) The base station of (19), wherein the symbols include quadratureamplitude modulation symbols.

(21) A user equipment for a mobile telecommunications system comprisingcircuitry configured to communicate with at least one base station,wherein the circuitry is further configured to:

-   -   receive symbols on a physical broadcast channel, wherein symbols        are transmitted with a subcarrier spacing and modulation symbols        are repeated in consecutive resource elements in the frequency        domain.

(22) The user equipment of (21), wherein the symbols include quadratureamplitude modulation symbols.

(23) The user equipment of (21) or (22), wherein the receiving of thesymbols includes decoding the repeatedly transmitted symbol based on thesubcarrier spacing.

(24) The user equipment of anyone of (21) to (23), wherein the receivingof the symbols includes decoding the repeatedly transmitted symbol basedon a second subcarrier spacing.

(25) A base station for a mobile telecommunications system comprisingcircuitry configured to communicate with at least one user equipment,wherein the circuitry is further configured to:

-   -   transmit symbols in a physical broadcast channel by applying a        phase ramp.

(26) The base station of (25), wherein each burst of the physicalbroadcast channel includes a reference symbol.

(27) The base station of (26), wherein the reference symbol is based ona Zadoff-Chu sequence.

(28) The base station of (27), wherein a root of the Zadoff-Chu sequencediffers from a root of a Zadoff-Chu sequence used for a primarysynchronization signal.

(29) The base station of anyone of (25) to (28), wherein the phase rampis based on a phase shift applied to a previous symbol.

(30) The base station of anyone of (25) to (29), wherein a phase shiftof the phase ramp is spread over 2π.

(31) A user equipment for a mobile telecommunications system comprisingcircuitry configured to communicate with at least one base station,wherein the circuitry is further configured to:

-   -   receive symbols over a physical broadcast channel, wherein a        phase ramp is applied to at least one symbol.

(32) The user equipment of (31), wherein the phase ramp is estimated onat least one symbol of a burst of the physical broadcast channel and aburst reference sequence.

(33) The user equipment of (31) or (32), wherein the phase ramp isdetected based on an inverse discrete Fourier transformation.

1. A base station for a mobile telecommunications system comprisingcircuitry configured to communicate with at least one user equipment,wherein the circuitry is further configured to: transmit symbols on aphysical broadcast channel, wherein symbols are transmitted with asubcarrier spacing and modulation symbols are repeated in consecutiveresource elements in the frequency domain.
 2. The base station of claim1, wherein the symbols include quadrature amplitude modulation symbols.3. A user equipment for a mobile telecommunications system comprisingcircuitry configured to communicate with at least one base station,wherein the circuitry is further configured to: receive symbols on aphysical broadcast channel, wherein symbols are transmitted with asubcarrier spacing and modulation symbols are repeated in consecutiveresource elements in the frequency domain.
 4. The user equipment ofclaim 3, wherein the symbols include quadrature amplitude modulationsymbols.
 5. The user equipment of claim 3, wherein the receiving of thesymbols includes decoding the repeatedly transmitted symbol based on thesubcarrier spacing.
 6. The user equipment of claim 3, wherein thereceiving of the symbols includes decoding the repeatedly transmittedsymbol based on a second subcarrier spacing.
 7. A base station for amobile telecommunications system comprising circuitry configured tocommunicate with at least one user equipment, wherein the circuitry isfurther configured to: transmit symbols in a physical broadcast channelby applying a phase ramp.
 8. The base station of claim 7, wherein eachburst of the physical broadcast channel includes a reference symbol. 9.The base station of claim 8, wherein the reference symbol is based on aZadoff-Chu sequence.
 10. The base station of claim 9, wherein a root ofthe Zadoff-Chu sequence differs from a root of a Zadoff-Chu sequenceused for a primary synchronization signal.
 11. The base station of claim7, wherein the phase ramp is based on a phase shift applied to aprevious symbol.
 12. The base station of claim 7, wherein a phase shiftof the phase ramp is spread over 2n.